Support structures for incorporation in a seat frame

ABSTRACT

A support structure for incorporation into a seat frame comprising a wire framework. The wire framework has two lateral suspended side wires, a plurality of transverse wires, one or more of the transverse wires being wound around the side wires and extending laterally beyond the side wires, and terminating in hook-like fingers. Either the fingers or select transverse wires are secured to the frame in order to suspend the structure.

This invention concerns an improved support structure for incorporationin a seat frame, and more especially such a structure comprising a wireframework of the kind having two lateral side wires adapted to besuspended in a seat frame and between which extend a plurality oftransverse wires providing load bearing support for upholstery of theseat.

Support structures of the aforementioned kind are very well known andmay have various configurations determined by the design of seat inwhich the support structure is to be mounted.

Whilst such support structures have proved advantageous in hithertoknown designs of seat, there is an increasing requirement, particularlyin relation to seats for motor vehicles, that the seat back shouldprovide adequate and anatomically correct support for an occupant of theseat in the lumbar region.

It is accordingly an object of the invention to provide a supportstructure of the aforementioned type that is capable of providingimproved lumbar support.

In accordance with the invention a support structure of theaforementioned type is characterised in that one or more transversewires extend laterally beyond the side wires after having been woundaround the latter and terminate in hook-like fingers that extendgenerally in a plane parallel to a surface of the seat to be supported.

The fact that the extended portions of the transverse wires terminate infree ends acting as fingers, rather than being connected to an edge wireas in hitherto known constructions, enables more versatile lateralsupport to be provided, particularly in the lumbar region of a backrest, as the fingers can be individually angled, if desired, to conformto the contour of the seat back. The hooked ends of the wire fingers mayalso provide a convenient means for the suspension of the supportstructure in a seat frame, serving as anchorages for tension springs orlike suspension means.

The fact that the laterally extending fingers are unconnected at theirfree ends also enables an effective adjustable lumbar support to beprovided by arching of the two side wires under the action of a tensionmeans, in known manner, as the freely extending fingers can providelaterally contoured support in the lumbar region without interferingwith the arching of the two side wires.

If desired the two side wires may be angled to provide regions of thesupport structure of differing transverse widths between these sidewires. Transverse wires extending between a wider section of the supportstructure may terminate at the side wires, so that the support structurecombines an area having the characteristics of a known flat support withan area having lateral support provided by the extended wire fingers inaccordance with the invention.

Further preferred features and advantages of the invention will becomeapparent from the following description taken in conjunction with thedrawings, in which

FIG. 1 is a front view of a support structure in accordance with oneembodiment of the invention, and

FIG. 2 is a similar view of a second embodiment of the invention.

Referring to FIG. 1, a support structure comprises a pair of side wires1 and 2 between which extend a plurality of transverse wires 3 that areanchored to the side wires 1 and 2 by being wound around the latter andthen extend beyond the side wires at 4 to terminate in hooked ends 5that extend generally in the plane of a surface of the seat to besupported.

In known manner the side wires 1 and 2 are provided with a covering ofpaper or plastic material that is gripped by the wound portions of thewires 3 and serves to maintain the spacing of the latter along the sidewires 1 and 2. The lower ends of the wires 1 and 2 as viewed in thedrawing are interconnected by a U-shaped transverse wire 6 of similargauge and construction to the wires 1 and 2, the wire 6 being secured tothe wires 1 and 2 by means of clips, in known manner. A similartransverse wire 7 is provided in the region of the upper ends of thewires 1 and 2.

The upper ends of the wires 1 and 2 are angled outwardly as illustratedand are secured to further L-shaped side wires 8 and 9 by means ofclips.

The clipping together of the separate wires 1, 8 and 2, 9 allowsrelative pivotal movement of the linked wires about a transverse axis asdescribed below.

The side wires 8 and 9 are of similar gauge and construction to thewires 1 and 2 and support further transverse wires 10 that are anchoredto the side wires in known manner. Also in known manner, the wires 10extend through a centre cord 11 of paper or synthetic plastic materialwhich serves to maintain the vertical spacing of the wires 10.

The support structure can be supported in a seat frame, indicated inbroken lines at 12 in FIG. 1, by means of tension springs indicated inbroken lines at 13, anchored between the seat frame 12, the side wires 8and 9 on the one hand and the hooked ends of upper and lower transversewires 3 on the other.

The support structure so far described could be used to providenon-adjustable lumbar support, but preferably means is provided foradjustable arching of the side wires 1 and 2 to enable horizontaladjustment of the lumbar support. For this purpose stirrup shaped wires14 and 15 are clipped to the wires 6 and 7 and provide support foranchor blocks 16 and 17 respectively supporting a cable 18 and outersheath 19 of a Bowden cable coupled to an actuating mechanism 20indicated in broken lines and mounted on the seat frame 12. Uponactuation of the cable mechanism, the two anchor blocks 16 and 17 aredrawn towards one another under tension thus causing the side wires 1and 2 to be arched in an adjustable manner in order to provide therequired lumbar support.

It will be appreciated that arching of the wires 1 and 2 does not causeundesired displacement of the side wires 8 and 9 in a horizontaldirection, as the side wires 8 and 9 can pivot relatively to the wires 1and 2 about a transverse axis.

If desired, means can also be provided for the vertical displacement ofthe complete support structure in the seat frame 12 for correspondingvertical adjustment of the position of lumbar support.

The arrangement described provides a novel and versatile supportstructure particularly for a vehicle seat. The upper part of the supportis of optimum width for support of the seat upholstery, whereas thedimension of the lower portion 10 the structure between the side wires 1and 2 is of the optimum width for providing lumbar support whilst thefinger ends of the side wires 3 can be cantilevered to form lateralwings providing sideways support in the lumbar region. All the requiredsupport is thus integrated in a single structure having the knownadvantages of the wire frame wherein the pitch and gauge of transversewires can be varied to match the suspension loading in a cost effectivemanner.

The hooks in the transverse wires 3 enable rapid assembly of thestructure in a seat frame and can also be used for trimming attachments.

The double cross wire support of the Bowden cable blocks braces theframe to enable application of the single cable tensioning mechanism tothe wire frame structure in a simple and economic manner.

If desired the support structure can be tapered to match a seat profile.

Vertical adjustment of the support structure is also facilitated byvirtue of the fact that the transverse wires linked to the tensionsprings 13 can flex in both the horizontal and vertical direction withmovement of the support structure.

A further embodiment of the invention is illustrated in FIG. 2 of thedrawings in which like components are indicated with the same referencenumerals as in FIG. 1, and will not therefore be described in furtherdetail.

In the arrangement of FIG. 2 the tension springs 13 are replaced byextended portions of the transverse wires 3 and 10 that hook directlyinto apertures in the seat frame 12.

Since the side wires of the support structure are thus linked to theseat frame by inextensible means, intermediate portions 3a and 10a ofthe transverse wires 3 and 10 are angled in the plane of the support asillustrated, in order that the support structure itself becomesextensible under loading placed upon the seat.

I claim:
 1. A support structure for incorporation in a frame of a seat, comprising a wire framework having two lateral side wires suspendible in the frame and between which extend a plurality of transverse wires which provide load-bearing support for upholstery of the seat, wherein one or more transverse wires extend laterally beyond the side wires after having been wound around the latter, characterised in that said one or more transverse wires terminate in free ends that can flex independently of one another relatively to a portion of the framework bounded by said side wires, the said free ends being formed into hook-like fingers.
 2. A structure as claimed in claim 1, further characterised in that the fingers are individually angled to conform to the contour of the seat surface and extend in a plane generally parallel to the wire framework.
 3. A structure as claimed in claim 1 or 2, further comprising tension springs extending between the seat frame and selected ones of said fingers.
 4. A structure as claimed in claim 1, further characterised in that the side wires are angled to provide regions of the structure of differing transverse width between the side wires.
 5. A structure as claimed in claim 4, further characterised in that at least some of the transverse wires (10) terminate at the side wires (8,9) in one or more regions of greater width.
 6. A structure as claimed in claim 1, further characterised in that a pair of stirrup shaped wires are fastened respectively to spaced-apart transverse wires each of which stirrup shaped wires provide support for an anchor block respectively supporting a cable and an outer sheath of a bowden cable coupled to an actuating mechanism adapted to be mounted on the frame, the arrangement being such that upon actuation of the mechanism in a first sense, the two anchor blocks are drawn towards one another under tension thus causing the side wires to become arched in an adjustable manner whilst actuation in a second sense causes the anchor blocks to move apart causing the side wires to become less arched. 